A Poké-BLOCK Party! (Japanese: 歌う！ポケモンからくり屋敷！！ Sing! Pokémon Trick House!) is the 39th episode of Pokémon: Advanced.
As Ash and co are a mere stone throw away from Mauville City, they soon notice a poster for the House of Tricks. Anyone who navigates this wacky maze will receive a grand prize of a year's supply of Pokéblock. Along the way, May meets a cute Jigglypuff, but Ash and Brock remember it all too well. Can anyone listen to its song all the way through?
The heroes have nearly arrived to Mauville City, but they see a poster, advertising the "House of Tricks", where the winner gets one-year supply of PokéBlocks. Team Rocket is also interested in getting the prize, even the Jigglypuff, with the marker. Ash wonders what the competition looks like, but Max is being knocked out by a Whismur. A young trainer, named Alanna, appears, scolding Whismur for going away on its own. The heroes introduce themselves, while Alanna explains the host, the King of Tricks, will explain everything. The King appears, who warns them it will take a lot of skill, intelligence and luck to pass his challenges. The Trick Master wishes them luck and goes away laughing, making May comment how "different the man is". Alanna points out the man shows up every year and makes these challenges. The heroes separate in different directions: Brock and Max take the right, Ash, his Pikachu, May and Alanna the left way. Team Rocket appears, also splitting in 2 groups.
While Alanna admits she is doing this challenge to improve her teamwork with Whismur, Jigglypuff is following them. Ash, May and Alanna have come to a maze, though Ash is confident he can overcome this with his eyes shut. Ash takes a way, but comes to a dead end, so May comments how he should shut his mouth first. Brock and Max have a dispute where to go. Despite Brock's warning, Max goes into another dead end. The King of Tricks appears before Ash, May and Alanna, mentioning the doors can be opened, but he stumbles upon a sponge room and drifts off. May claims he is crazy, but Alanna corrects her, claiming the King of Tricks is just different. James and Meowth notice the twerps and Meowth plans to take Whismur, for their boss will know what time it is when Whismur makes sounds. Ash, May and Alanna have split up and May and Ash have goe to dead ends. Whismur and Alanna split up, but Whismur gets captured by James and Meowth. Alanna tries to find it, with Ash and May helping her. Jessie notices them and plans to capture Pikachu. Just as Jessie stalks, Pikachu turns around and notices her, so she goes back.
Jigglypuff appears before Ash, May and Alanna, then starts to sing, causing them to get sleep. When they wake up, May and Alanna laughs at one another, but Ash explains Jigglypuff's Sing causes them to be asleep and, since it gets annoyed everyone went to sleep and did not hear its song, Jigglypuff draws on their faces. Everyone goes away, leaving Jessie asleep. James and Meowth reunite with Jessie. Meowth claims they only have to get the PokéBlocks and runs off, but bashes into a wall. Ash, May and Alanna reunite with Brock and Max as well. They think Whismur got out already they are going to see at the exit. Max claims there must be trap doors and knocks on a wall, only to find the exit. The heroes have got out of the maze, impressing the King of Tricks. He falls down, worrying May he will get hurt, but Alanna reminds them the King of Tricks does these things every year. Team Rocket has got out as well, and while they go, Alanna sees her Whismur found. Alanna thanks them for finding Team Rocket, who is startled, as they did not intend to give Whismur back.
Jigglypuff appears once more and sings, causing everyone to be asleep but Whismur. Seeing Whismur did hear out its song, Jigglypuff is cheering with Whismur. Once everyone wakes up May and Alanna laugh once more, while others are getting their marks off. Whismur hasn't been scribbled on and Max explains the Soundproof ability causes Whismur to be immune to sound moves. When Team Rocket wakes up, they are sad they lost the twerps, but Meowth claims they need to continue. The next challenge is to pass the stream, by walking on the logs. The King of Tricks appears again, warning some of the logs are not safe to pass. The King of Tricks falls into the water, as the log he was standing is not safe. May points out the King of Tricks has issues, but Alanna claims he is fun, too. Team Rocket appears and Jessie "accidentally" pushes the log, causing the twerps to fall down, into the stream, angering them. The next challenge is to swing the rope to the other side, a challenge Team Rocket has already succeeded. The King of Tricks takes a swing, but warns if it is a wrong one, the rope would be too long and they could bash into a wall. May wonders if the King of Tricks has hit the wall too many times, but Alanna is confident he's just nuts. Everyone takes a swing, but Team Rocket uses an arm, causing everyone to be pushed away and fall down.
The next challenge is to climb the rope, but the King of Tricks takes a wrong rope, causing a hammer to bash him. The King of Tricks falls on the floor, displeasing May he got hurt, but Alanna reminds her the King always comes back every year. Ash chooses the red box and everyone climbs the rope towards it. Just before the end, James appears and cuts the rope and Team Rocket taunts the twerps. The next challenge is to cross the sand without falling into a hole. Team Rocket is confident to win, as they dig holes all the time. However, when they make their first step, they fall down. The King of Trick demonstrates one could fall into a hole and does so himself. May suspects the King is just lonely, but Alanna says he must be for many years. Ash is confident the path is safe, since he has been "practicing" by falling into Team Rocket's holes. However, he soon falls into a pitfall, so May claims Ash just needs more practice.
The last room seems empty, so Alanna suspects they are near the end. Team Rocket, in disguise, tells the last challenge is to jump 10 times around the rope. The heroes do so, but the Team Rocket ties them up and steal Pikachu and Whismur, then take off their disguises. Ash sends Corphish, who cuts the ropes, but Jessie sends Seviper and James his Cacnea. Cacnea uses Pin Missile, but Corphish takes less damage, due to its Harden move. Corphish uses Crabhammer and knocks Cacnea out. Seviper wraps Whismur, but Whismur uses Screech, hurting everyone's ears. Whismur uses Supersonic, affecting Seviper to free itself. Whismur uses Hyper Voice and Corphish Crabhammer, blasting Team Rocket off. After the battle, Alanna hugs Whismur. The winner who passed the House of Tricks is Ivan, from Mauville City, who receives the PokéBlocks. Ivan drops the boxes, causing the King of Tricks to advise everyone to watch out. May comments the king could make better jokes, but Alanna is certain this year's jokes were better than last year's. May feels a bit bad since Alanna didn't win the prize, with Team Rocket ambushing them, but Alanna thinks it was great when Whismur battled with them, who is tired and goes to sleep. Brock and Max point out Mauville City is not far ahead, pleasing Ash he will obtain his third badge.
Jigglypuff appears once more and sings its song, making everyone asleep. Jigglypuff notices Whismur, but sees it is also asleep (due to exhaustion). Jigglypuff leaves with everyone having marks on their faces.
- "That Jigglypuff thinks it's a star, so if you fall asleep when it sings, it will get mad." - Ash, warning May and Alanna about Jigglypuff
- Featured Pokémon: Seviper.
- This is the last appearance of Jigglypuff in the anime so far.